Got it to work. Select C5550 series. The printer is a PAIN to use. Make sure you have clearance in the back for the CD to pass through, or it will pretend like it does not see the tray rather than telling you the printer is does not have clearance in the back, which it should be able to detect because the tray does not pass through. You'll need to set the printer about 6 inches from the wall to get it to work correctly. If you are printing to paper, you need to remove the tray and click the CD/DVD platform in the up position to print. Its a very non intuitive process, but with persistence you can get it to work. Disc Cover folks, it should remember US Letter and not make me select a paper type each time. My selection should stick.

Are you sure that the C5550 printer doesn't work with the standard paper format? I mean, in the Disc Cover Print dialog, you can click the Select Format button and choose "HP Photosmart series". It sets 5.12*5,12 in format.